Burning coal produces solid wastes such as bottom and fly ash, as well as flue gases containing SOx compounds. The flue gases containing SOx compounds are subjected to flue gas desulfurization (FGD) treatment processes in dedicated FGD treatment systems.
The POD treatment systems often are so-called “wet scrubbing” systems that remove 90% or more of the SOx compounds, but generate wastewater that contains a variety of different contaminants. Thus, that wastewater requires treatment before release into the environment. A variety of treatment methodologies are employed to remove the various types of contaminants. One of those contaminants is boron which is frequently removed by selective ion exchange during one part of the treatment process. Such selective ion exchange systems/processes often times remove the boron down to a concentration of less than about 5 mg/l (measured as B).
The selective ion exchange system utilizes well known resins, often in bead form, to strip the boron from the FGD wastewater stream. However, such ion exchange systems require periodic regeneration to restore the resin to its initial stripping capability and efficiency. Often times, a 4-6% sulfuric acid or hydrochloric acid solution is introduced into the resin to strip the boron from the resin.
This acid regeneration step creates another type of waste liquid, namely an acid regeneration liquid or solution. Thus, there is a need to treat such ion exchange system regeneration liquids.